This invention relates to an ink or form roller unit for an off-set rotary printing press. More particularly, the present invention relates to apparatus for the delivery of a fluid such as ink to such a printing press by either continuous or intermittent transfer from a fountain roller.
A basic distinction exists between film inker units and lifter inker units in ink or form roller units for an off-set rotary printing press. In a film form roller unit a continuous or continuing transfer of ink between an ink fountain roller and an inker unit located down stream therefrom. In lifter inkiers, the ink transfer is made intermittently by means of a lifter roller which oscillates or moves back and forth. Film inker units have the advantages that they work faster and can transfer more ink because of the continuous operation and they do not embody a design of oscillating elements. Lifter inkers, on the other hand, have the advantage of a more accurate metering of ink especially when transferring smaller amounts of ink.
A number of ink or form roller units already have been disclosed for changing from film to lifter operation and back in order to unite the advantages of both inker unit designs. The advantages of both types of inker units are equally valid for transferring materials other than ink. The inker or form roller units which can be changed from film to lifter operation and reversed are usually very complicated and constructed of many parts. Sometimes, changing from one mode of operation to another mode of operation is complicated and time consuming. Finally, with respect to known designs, of certain reversible ink-and-form roller units they have the disadvantage that one or several rollers are not used in one or the other modes of operation, i.e., such rollers are not used for ink transfer. A negative consequence rising out of the non-use of some of the rollers is that the non-used rollers must be cleaned thoroughly so they can be used when the mode of operation requiring their use is again selected because during an idle non-use period, the ink or other material which is on the rollers during the period of non-use dries. Even if the rollers are cleaned after the change in mode of operation, but before a start-up operation of the printing press while the ink or other material has not dried, there is still a rather substantial work factor, consumption of time and a standstill period of the complete press.